<!DOCTYPE html>
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<html>
    <head>
        <meta charset="UTF-8">
        <title>计算2+2+..+280</title>
    </head>
    <body>
        <?php
       $sun=0;
       for($i=1;$i<=280;$i++)
       {
           if($i%2==1)
           {
               continue;
           }
           $sun=$sun+$i;
       }
       echo "2+4+6+8...+280=".$sun;
        ?>
    </body>
</html>
